Broad Goal: To participate in all collaborative activities relevant to the mission of the Global Network including the development and leadership of Common Network projects as exemplified by Preconception Maternal Nutrition. Study Objective: Determine the public health benefits in resource-poor populations of providing a comprehensive nutrition supplement to women of reproductive age commencing S3 mo. prior to conception (Arm 1, PC) in comparison with starting the same supplement at 12 wk. gestation (Arm 2, PG) or provision of iron/folate alone (Arm 3, IPS). Primary outcomes: (1) length-for-age Z-score (LAZ) at 7 d postpartum; (2) LAZ at 6 mo. of age. Secondary outcomes include: comparing arms for fetal length; birth weight; incidence of low birth weight; incidence of perinata and early infancy (<6 mo.) mortality and severe infectious disease morbidity. Research Design & Methods: Multi-site randomized controlled efficacy trial. Each arm will include 800 women divided equally among sites. The first 100 of each arm in each site to conceive continue interventions <6 mo. postpartum. Inclusion criteria: para 1-2, <26 yr., enrolled through Global Network Maternal Neonatal Health Registry (MNHR); algorithms based on MNHR data to enroll at 12 3 mo. post-partum. Arm 1 commences intervention at enrollment; Arms 2 and 3 receive IPS from enrollment with Arm 2 switching to same supplement as Arm 1 at 12 weeks gestation. Intervention provides 100 kcal/d as a lipid-based multi-micronutrient (MMN) product, with increasing energy to 500 kcal/d and protein to 25g/d if BMI <20 or pregnancy weight gain is low. Baseline parental, fetal (ultrasound), birth weight, early neonatal (7 d) and infant anthropometry (3 and 6 mo.); longitudinal maternal blood, subsample cord blood & placenta samples will be collected by trained Network and Health personnel. Mortality and morbidity data will be collected from MNHR. The primary analyses will compare LAZ at 7 days for Arm 1 vs. Arms 2 and 3 controlling for site. The results of this study have potentially profound implications for the impat of nutrition interventions initiated prior to conception, and for the reversibility of adverse intergenerational effects, including linear growth failure.